This invention relates generally to mine ventilation and, more particularly, to mine doors and mine stoppings.
So-called "stoppings" are widely used in mines to stop off the flow of air in passageways in the mines, a "stopping" generally being a masonry (e.g., concrete block) or metal wall installed at the entrance of a passageway to block flow of air therethrough. Such stoppings are typically provided with a doorway or opening and a door therein for occasional access to the blocked-off passageway. This arrangement is satisfactory under usual conditions when the stopping should prevent the passage of air through the passageway. In some conditions, however, high pressure concussive air is forced against the stopping and door. This may occur, for instance, in longwall mining where a large roof can collapse very rapidly and displace a large amount of air, thereby creating a shock wave of high pressure concussive air. Likewise, a mine blast will also force high pressure concussive air against the stopping and the door. In conventional stopping arrangements, the concussive air cannot escape through the stopping without causing significant damage to the stopping, the door or both.
Moreover, prior art stoppings are constructed generally perpendicular to the direction of air flow through the passageway. This construction is not optimal for decreasing the stress on the stopping caused by the concussive air.